Enhanced thermoelectric response in the fractional quantum Hall effect

TL;DR

This paper investigates the thermoelectric response of a quantum dot in a fractional quantum Hall system, revealing enhanced efficiency due to electron fractionalization, with theoretical expressions showing increased ZT and Seebeck coefficient for fractional fillings.

Contribution

It provides the first detailed analysis of thermoelectric properties in fractional quantum Hall states, highlighting the impact of electron fractionalization on thermoelectric efficiency.

Findings

ZT and Seebeck coefficient increase with fractional filling factor m.

Significant enhancement of thermoelectric response in fractional vs. integer quantum Hall states.

Explicit low-temperature expressions for Onsager coefficients.

Abstract

We study the linear thermoelectric response of a quantum dot embedded in a constriction of a quantum Hall bar with fractional filling factors nu=1/m within Laughlin series. We calculate the figure of merit ZT for the maximum efficiency at a fixed temperature difference. We find a significant enhancement of this quantity in the fractional filling in relation to the integer-filling case, which is a direct consequence of the fractionalization of the electron in the fractional quantum Hall state. We present simple theoretical expressions for the Onsager coefficients at low temperatures, which explicitly show that ZT and the Seebeck coefficient increase with m.